Study on Stiffness Variation of Rock Bolt Grout by the Blast Vibration in the Underground Cavern

doi:10.12972/ksmer.2014.51.1.68

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2014 Vol.51, Issue 1 Preview Page Next Page

Research Paper

Study on Stiffness Variation of Rock Bolt Grout by the Blast Vibration in the Underground Cavern 지하 공동 내 발파진동으로 인한 록볼트 그라우트 강성 변화 연구: 정진·김기호·문홍주·노영목·장원일
Jin Jung, Ki-Ho Kim, Hong-Ju Mun, Young-Mok Noh and Won-Yil Jang

28 February 2014. pp. 68-77

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Abstract

There is a growing trend towards underground space application in these days. Rock bolt system is known as the most economic system to support reinforcement of the origin rock conditions. But when the system is exposed to the secondary factor, which like blast vibration, their supporting capacity could be weaken. Thus, it could affect stability of the underground space. So we verified the effect of continuous blast vibration to the rock bolt grout, through the numerical analysis and scaled model test. As a result, pullout loads are gradually reduced and converged as a constant value by increasing the blasting number. Also, after 20 times of the blast vibration, axial force is converging, the displacement of rock bolt grout, which is one of the parameters affect the stiffness, is increased continuously. After blasting is performed 20 times, we verified that the stiffness has changed about 72% compared to the initial stiffness.c

Keywords

Blast vibration

Rock bolt

Scaled model test

Stiffness

최근 지하공간 개발 활용이 늘어나고 있는 추세이며 록볼트 시스템은 이러한 지하공간 개발에서 가장 보편적으로 사용되고 있는 보강재 이다. 하지만 록볼트 시스템은 발파진동과 같은 2차적인 요인에 노출될 경우 자체의 보강 능력 상실이 우려되어 공동의 안정성에 영향을 미칠 수 있다. 따라서 지속적인 발파진동이 록볼트 그라우트에 미치는 영향을 파악하기 위하여 축소모형실험과 수치해석을 수행하였다. 그 결과 발파횟수가 증가 할수록 인발하중은 점차 감소를 하며 일정한 값에 수렴하는 것을 확인하였다. 또한 강성에 영향을 미치는 변수 중 하나인 록볼트 그라우트의 변위를 파악한 결과 축력이 수렴하는 20회의 발파진동 이후에도 변위는 지속적으로 증가하는 양상이 나타났으며, 20회 발파 수행 후 강성은 초기에 비해 약 72%의 변화가 발생하는 것을 확인하였다.

키워드

발파진동

록볼트

축소모형실험

강성

References

Hobbs, D.W., 1966, “Scale model study of strata movement around mine roadways. Appratus, technique and some preliminary results,” Int. J. of rock Mech. Min. Sci., Vol. 3, pp. 101-127.
Itasca Consulting Group, INC., 2007, 3DEC-Theory and Background, Version 4.1, Minneapolos:ICG.
Jeon, S.S., Kim, D.S. and Jang, Y.W., 2007, “Stability Assessment of Concrete Lining and Rock Bolts of the Adjacent Tunnel by Blast-Induced Vibration,” J. of the Korean Society for Geotechnical Engineering, Vol. 23, No. 10, pp. 33-45.
Jeon, S.W., Kim, J.W., Hong, C.W. and Kim, Y.K., 2003, “Effect of a karstic lime cavern on the stability of tunnel - A scaled model test,” J. of the Korean Society for Geosystem Engineering, Vol. 40, No. 3, pp. 147-158.
Jong, Y.H., Lee, C.I. and Choi, Y.K., 2006, “Stability Assessment of an Adjacent Ground Storage Tank by Blast-induced Vibration,” J. of the Korean society for noise and vibration engineering, Vol. 16, No. 1, pp. 19-26.
Kim, J.Y., Jeon, S.W. and Suh, Y.H., 2004, “A study on the effect of underground openings on the stability of surface structures using scaled model test,” J. of the Korean Society for Rock Mechanics, Vol. 14, No. 1, pp. 43-53.
Lee, S.C., Kim, Y.G. and Lee, H.K., 1992, “Deformation Behaviors Around a Circular Opening Considering Orientation of Joint and Condition of Earth Pressure,” J. of the Korean Society for Geosystem Engineering, Vol. 29, No. 1, pp. 1-9.
Lee, H.K. and Yang, H.S., 1990, “Scaled model test and numerical analysis for rock behaviors around the excavating opening with discontinuous model materials,” J. of the Korean Society of Mineral and energy Resources Engineers, Vol. 27, No. 6, pp. 390-411.
Lee, Y.K., Lee, C.I. and Cho, T.J., 1995, “A study on the visco-plactic behavior of the jointed rock mass reinforced by rockbolts during excavation,” J. of the Korean Society for Rock Mechanics, Vol. 5, pp. 123-133.
Lim, H.U. and Lee, C.I., 1991, “The trends and vatiations of natural stresses in rock masses with depth,” J. of the Korean Society for Rock Mechanics, Vol. 1, No. 1, pp. 91-101.
Liu, Q. and Tidman, P., 1995, Estimation of the dynamic pressure around a fully loaded blasthole, Technical Report MRL, CANMET/MRL.
National Highway Institute., 1991, Rock Blasting and Overbreak Control.
Park, B.K., Jeon, S.W., Park, G.J., Do, D.S., Kim, T.H. and Jung, D.S., 2005, “Assessment of Blast-induced Vibration Using Dynamic Distinct Element Analysis,” J. of the Korean society for noise and vibration engineering, Vol. 15, No. 12, pp. 1389-1397.
Sunwoo, C., Jung, S.G., Choi, S.W., Jung, Y.B., Jeon, Y.S. and Lee S.G., 2004, A Study on the Safety and Environmental Control of Underground Opening in Limestone Quarries, Technical Report KR/04/17.

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society of Mineral and Energy Resources Engineers
Journal Title(Ko) :한국자원공학회지
Volume : 51
No :1
Pages :68-77
DOI :https://doi.org/10.12972/ksmer.2014.51.1.68

[1] Hobbs, D.W., 1966, “Scale model study of strata movement around mine roadways. Appratus, technique and some preliminary results,” Int. J. of rock Mech. Min. Sci., Vol. 3, pp. 101-127.

[2] Itasca Consulting Group, INC., 2007, 3DEC-Theory and Background, Version 4.1, Minneapolos:ICG.

[3] Jeon, S.S., Kim, D.S. and Jang, Y.W., 2007, “Stability Assessment of Concrete Lining and Rock Bolts of the Adjacent Tunnel by Blast-Induced Vibration,” J. of the Korean Society for Geotechnical Engineering, Vol. 23, No. 10, pp. 33-45.

[4] Jeon, S.W., Kim, J.W., Hong, C.W. and Kim, Y.K., 2003, “Effect of a karstic lime cavern on the stability of tunnel - A scaled model test,” J. of the Korean Society for Geosystem Engineering, Vol. 40, No. 3, pp. 147-158.

[5] Jong, Y.H., Lee, C.I. and Choi, Y.K., 2006, “Stability Assessment of an Adjacent Ground Storage Tank by Blast-induced Vibration,” J. of the Korean society for noise and vibration engineering, Vol. 16, No. 1, pp. 19-26.

[6] Kim, J.Y., Jeon, S.W. and Suh, Y.H., 2004, “A study on the effect of underground openings on the stability of surface structures using scaled model test,” J. of the Korean Society for Rock Mechanics, Vol. 14, No. 1, pp. 43-53.

[7] Lee, S.C., Kim, Y.G. and Lee, H.K., 1992, “Deformation Behaviors Around a Circular Opening Considering Orientation of Joint and Condition of Earth Pressure,” J. of the Korean Society for Geosystem Engineering, Vol. 29, No. 1, pp. 1-9.

[8] Lee, H.K. and Yang, H.S., 1990, “Scaled model test and numerical analysis for rock behaviors around the excavating opening with discontinuous model materials,” J. of the Korean Society of Mineral and energy Resources Engineers, Vol. 27, No. 6, pp. 390-411.

[9] Lee, Y.K., Lee, C.I. and Cho, T.J., 1995, “A study on the visco-plactic behavior of the jointed rock mass reinforced by rockbolts during excavation,” J. of the Korean Society for Rock Mechanics, Vol. 5, pp. 123-133.

[10] Lim, H.U. and Lee, C.I., 1991, “The trends and vatiations of natural stresses in rock masses with depth,” J. of the Korean Society for Rock Mechanics, Vol. 1, No. 1, pp. 91-101.

[11] Liu, Q. and Tidman, P., 1995, Estimation of the dynamic pressure around a fully loaded blasthole, Technical Report MRL, CANMET/MRL.

[12] National Highway Institute., 1991, Rock Blasting and Overbreak Control.

[13] Park, B.K., Jeon, S.W., Park, G.J., Do, D.S., Kim, T.H. and Jung, D.S., 2005, “Assessment of Blast-induced Vibration Using Dynamic Distinct Element Analysis,” J. of the Korean society for noise and vibration engineering, Vol. 15, No. 12, pp. 1389-1397.

[14] Sunwoo, C., Jung, S.G., Choi, S.W., Jung, Y.B., Jeon, Y.S. and Lee S.G., 2004, A Study on the Safety and Environmental Control of Underground Opening in Limestone Quarries, Technical Report KR/04/17.

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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